Physical characteristics, such as a friction coefficient, of a clutch as a power transmission mechanism interposed between a driving force source and driving wheels change due to a change with time.
Patent Literature 1 (Japanese Patent Application Laid-Open Publication No. 2015-83860) discloses a method in which an estimated friction coefficient of a friction material of a clutch is calculated based on a clutch pressing force and input torque input to the clutch, a difference between the estimated friction coefficient and a predetermined friction coefficient of the friction material is calculated and stored as a learning value, and the engagement pressure to be applied to the clutch is corrected using this learning value.
In Patent Literature 1, the engagement pressure is corrected only in consideration of a change with time in the friction coefficient of the clutch. However, due to a change with time in an internal return spring, the minimum control pressure for the clutch required to make the torque capacity larger than zero (to start torque transmission) also changes. Therefore, it is necessary to control the clutch in consideration of a change in the control pressure. In Patent Literature 1, the change with time of this control pressure is not considered.
The present invention has been made in view of the above-described circumstances and an object thereof is to provide a vehicle control device capable of accurately transmitting necessary torque to driving wheels by a power transmission mechanism interposed between a driving force source and the driving wheels.
Provided is a vehicle control device for a vehicle related to the invention, in which the vehicle has a driving force source, driving wheels, and a power transmission mechanism that is interposed between the driving force source and the driving wheels and controls transmission of a driving force from the driving force source to the driving wheels by using a frictional force. The vehicle control device includes: a transmission torque acquisition unit configured to acquire a first transmission torque transmitted by the power transmission mechanism in a first state in which a control pressure of the power transmission mechanism is controlled to a first pressure value, and a second transmission torque transmitted by the power transmission mechanism in a second state in which the control pressure of the power transmission mechanism is controlled to a second pressure value; a storage unit configured to store control data indicating a relationship between a transmission torque of the power transmission mechanism and a control pressure of the power transmission mechanism required to obtain the transmission torque, the control data including friction coefficient data indicating a relationship between a friction coefficient of the power transmission mechanism and a surface pressure to be applied to a friction material of the power transmission mechanism, which is obtained by subtracting a set value of touch point pressure set as a minimum control pressure of the power transmission mechanism required to start transmission of the torque by the power transmission mechanism from the control pressure of the power transmission mechanism; a controller configured to control the power transmission mechanism based on the control data; and a correction unit configured to correct the control data. And the correction unit is configured to: calculate a first friction coefficient which is a friction coefficient of the power transmission mechanism in the first state based on the friction coefficient data and the first pressure value; calculate a second friction coefficient which is a friction coefficient of the power transmission mechanism in the second state based on the friction coefficient data and the second pressure value; calculate an estimated value of the touch point pressure based on the first pressure value, the first transmission torque, the first friction coefficient, the second pressure value, the second transmission torque, and the second friction coefficient; and correct the control data based on the estimated value.
According to the present invention, it is possible to provide a vehicle control device capable of accurately transmitting necessary torque to driving wheels by a power transmission mechanism interposed between a driving force source and the driving wheels.